1. Technical Field
Example embodiments relate to a semiconductor device, and more particularly to a memory device and a memory system having the memory device.
2. Description of the Related Art
Generally, a volatile memory device such as a dynamic random access memory (DRAM) stores data by charging a capacitor. Since the charge stored in the capacitor may leak with a passage of time, the volatile memory device is typically required to perform a refresh operation periodically.
As a fabrication process of the memory device is scaled down, space between word-lines becomes narrower. Therefore, disturbance phenomenon occurs more frequently than before, during which charge of a memory cell connected to one word-line is influenced by voltage distribution of adjacent word-lines.
When one particular word-line is intensively accessed, the disturbance phenomenon increases in which the charge of the memory cell connected to neighboring word-lines adjacent to the particular word-line may be lost due to an activated voltage of the particular word-line.